Performance of a screening algorithm for chlamydial infection in 2 samples of patients in general practice

This paper evaluates the performance of an algorithm developed for opportunistic, selective screening of women for chlamydial infection in general practice in Antwerp, Belgium. Its performance was examined in 2 independent sets of patients: A) a cohort of 326 women participating in a pilot screening study, and B) a sample of 25 Chlamydia positive women, identified from the records of a laboratory of clinical microbiology. For group A, positive and negative predictive values were calculated and the accuracy of the algorithm was assessed. For group B, we examined the proportion of patients complying with the algorithm. In group A, the screening algorithm would have detected 73% of the cases in 35.6% of the population. The positive and negative predictive values were 7.7% and 98.4%, respectively. In group B, 84% of patients complied with the algorithm. The screening algorithm worked reasonably well in 2 datasets from a similar population studied 2 y later, but needs further validation.